A tiny ferry making its way across the Clyde river got caught up in a NATO naval exercise and ended up being threatened by a large US battleship, it emerged this week.

The 70-year-old boat was starting the 15 minute crossing from Gourock to Kilcreggan when it received a radio message: "Unidentified vessel approaching on my starboard side, please identify yourself. If you fail to do so, we will open fire on you with live ammunition."

The US ship had just left Faslane Naval base.

A source told the Daily Record: "The skipper got a real fright and radioed him back, saying he was just a wee ferry.

"If you've got a big battleship loaded with guns bearing down on you and threatening to shoot, it's quite scary."

The message was broadcast on channel 16 - usually reserved for emergencies. Commander Don Chalmers, in charge of the excercise, apologised to the rattled ferry captain.